Hi, My car is a honda fit 2006 model and I have these weird 2 problems on my car. First is an idle problem where in if I start the car, usually from cold start, when I shift the transmission from Park to Drive, my rpm went down to like 400 to 500 then it will go up again for about 750 then down again to 400, I recently changed my spark plugs, all of them, I also changed one of the ignition coil at the rear and also I have cleaned my throttle.

Second weird problem is when I change the transmission from Park to Reverse, when I am still at reverse, the climate of my aircon changed, like the coldness get changed, is it normal?

please help me folks, I really appreciate it.